Fluorocarbons (compounds that contain both carbon and fluorine) were, until recently, used as refrigerants. The compounds listed in the following table are all gases at 25 °C, and their solubilities in water at 25 °C and 1 atm fluorocarbon pressure are given as mass percentages. (a) For each fluorocarbon, calculate the molality of a saturated solution.

Key Concepts

Molality

Molality is a measure of the concentration of a solute in a solution, defined as the number of moles of solute per kilogram of solvent. It is particularly useful in situations where temperature changes may affect the volume of the solution, as it is based on mass rather than volume. To calculate molality, one must know the mass of the solute and the mass of the solvent, allowing for accurate concentration measurements in various chemical contexts.

Saturated Solution

A saturated solution is one in which the maximum amount of solute has been dissolved in a solvent at a given temperature and pressure. Beyond this point, any additional solute will not dissolve and will remain as a solid. Understanding saturation is crucial for calculating molality, as it determines the amount of solute present in the solution, which is necessary for further concentration calculations.

Solubility

Solubility refers to the ability of a substance (solute) to dissolve in a solvent at a specific temperature and pressure, often expressed in terms of mass percentage or molarity. In the context of fluorocarbons, solubility indicates how much of the gas can be dissolved in water, which is essential for determining the concentration of the solution. This property is influenced by factors such as temperature, pressure, and the nature of the solute and solvent.